System and method for controlled delivery of medical devices into patient bodies

ABSTRACT

Intravascular delivery system for deployment of a therapeutic device, such as a stent, in a controlled and robust manner is supported by a lockable balloon catheter equipped with a locking mechanism configured to lock in vivo to a delivery component, such as a guidewire. The lockable balloon catheter can be controllably transitioned between a locked and an unlocked modes of operation by inflation/deflation of the balloon of the lockable balloon catheter. Being in the locked mode of operation, the lockable balloon catheter facilitates delivery of the therapeutic element along the delivery component to a target site while enhancing the stability of the delivery component, especially near the target site.

FIELD OF THE INVENTION

The present invention is directed to medical devices, and, inparticular, to minimally invasive devices which are used for treatmentwithin the human (or animal) body internal passages, such as, forexample, vasculature (such as blood vessels), or bile duct, as well asrenal ureteric duct, etc.

The subject invention further addresses a delivery system forpercutaneous coronary intervention adapted, for example, forintravascular balloon angioplasty.

The present invention is also directed to medical devices designed forintravascular deployment of therapeutic elements, such as, for example,stents, using a balloon catheter that is lockable in vivo to a deliverycomponent, such as a guidewire.

In overall concept, the present invention is directed to a system andmethod for deployment of a therapeutic element, such as a stent, in apatient's body internal passages (for example, intravascular, or otherinternal tube-like structures in a patient's body) in a controlledrobust manner which permits a reduction of a number of equipmentexchanges needed to deploy the therapeutic element at a lesion sitewithin an internal tube-like structure (for example, a blood vessel, ina patient's body) while securing a delivery component, such as aguidewire, within the blood vessel during advancement of the therapeuticelement to the lesion site.

Further, the present system is directed to a balloon catheter which isprovided with a locking mechanism to lock in vivo to a deliverycomponent, e.g., a guide wire, inserted into the blood vessel undertreatment, where the locked balloon catheter facilitates delivery ofadditional components (such as a therapeutic delivery catheter) alongthe delivery component (the guidewire) to a target site for treatmentwhile enhancing the stability of the delivery component, when inproximity to the target site.

The present invention is also directed to an intravascular deliverysystem supported by a balloon catheter equipped with a mechanism toanchor and stabilize a guidewire near the target site for superiordelivery of additional intravascular components along the guidewire byminimizing movement of the distal end of the guidewire within the bloodvessel, thereby enhancing guidewire stability in vivo.

The present invention is also directed to an intravascular kinkresistant delivery system which is reinforced by an external rail (or abuddy system) to help advancement of the additional intravascular device(such as a stent) to the lesion.

In addition, the present invention is directed to a method of using thedelivery system where a balloon catheter is delivered to a lesion in ablood vessel over a guidewire and the balloon of the balloon catheter isinflated with a conventional balloon inflation mechanism to dilate theblood vessel and disrupt the lesion. The balloon then is deflated, andmoved adjacent to the lesion, and the balloon catheter is locked to theguidewire by inflating the balloon. Subsequently, one or more additionalintravascular components may be delivered to the lesion, while theballoon catheter remains locked to the guidewire to anchor and stabilizethe guidewire within the blood vessel.

BACKGROUND OF THE INVENTION

Ischemic cardiovascular syndromes affect blood flow by narrowing,weakening, or blocking a blood vessel, often resulting from the buildupof material (referred to herein as a lesion) within the blood vessel.Ischemic cardiovascular syndromes may include the coronary vascularsyndrome, sometimes referred to as coronary artery disease (CAD),generally associated with blood vessels leading to/from the heart, aswell as the peripheral vascular syndrome, commonly referred to as theperipheral artery disease (PAD), associated with blood vessels which donot lead to/from the heart or the brain.

Endovascular treatment for ischemic cardiovascular syndromes permitsaccess to vascular lesions through percutaneous introduction ofcatheters through a blood vessel, such as, for example, the femoralartery, and therefore involves less patient trauma than an open surgicalapproach.

Percutaneous transluminal angioplasty of coronary and peripheralarteries (PTCA and PTA, respectivel) are widely accepted as therevascularization procedures of choice in patients with ischemiccardiovascular syndromes (e.g., chronic and acute coronary ischemicsyndromes) and peripheral ischemic syndromes (such as the chronic limbischemia, including claudication and critical limb ischemia).

However, the use of the conventional percutaneous treatments may belimited due to re-occlusion or restenosis. This could be due to theexuberant proliferation of smooth muscle cells that grow to occlude thetreated vessel segment, progression of atherosclerotic plaque ornegative remodeling of the treated segment causing reoccurrence ofsymptoms. Re-occlusion, or restenosis, may necessitate potentialre-intervention for additional treatment.

Various adjuncts to angioplasty seek to reduce restenosis throughnumerous techniques. These techniques may include extractional,rotational, orbital, or laser atherectomy, as well as the use of baremetal and bare nitinol stents. More recently, drug eluting stents (DES)started to be used to treat/prevent restenosis. The latter technologyhas been demonstrated to significantly reduce coronary artery restenosiswhen compared to angioplasty or bare metal stents.

In peripheral arteries, the use of bare nitinol stents has been shown tobe superior to balloon angioplasty alone and has emerged as the“default” percutaneous strategy for the treatment of chronic limbischemic syndromes, particularly in complex disease patterns involvingthe femoropopliteal artery.

Stents have been customarily used for treating occlusive vasculardisease. For example, U.S. Pat. No. 5,135,536 to Hillstead and U.S. Pat.No. 5,314,444 to Gianturco describe a stent which comprises anexpandable wire tube having a reduced diameter for transluminalplacement. Once the stent is positioned within a vessel, a ballooncatheter is used to expand the stent to support and reinforce the fullcircumference of the vessel. Such prior art stents typically have highradial strength to resist collapse due to vessel disease.

In the conventional procedure for a stent delivery followingpercutaneous transluminal angioplasty, initially a guidewire ispercutaneously advanced to the lesion within a blood vessel.Subsequently, an angioplasty balloon catheter is advanced over theguidewire to the lesion. The angioplasty balloon catheter may beadvanced in an over-the-wire (“OTW”) manner or in a rapid exchange(“RX”) manner. When in place, the balloon is inflated to expand theblood flow channel within the blood vessel at the lesion site.

In a subsequent step, the angioplasty balloon catheter is removed fromthe blood vessel while the guidewire remains in place, and a stentdelivery balloon catheter is advanced over the guidewire to the lesionfor stent delivery.

A drawback of the conventionally performed procedure is the limitedsafety and the difficulty of advancing the stent delivery ballooncatheter across the lesion, even subsequent to the angioplasty due tothe fact that the guidewire does not always constitute a sufficientlystable structure for the catheter advancement in the blood vessel. Forexample, the free distal tip of the guidewire can uncontrollably movearound within the blood vessel. The uncontrollable motion of the distalend of the guidewire may cause its retraction into the guidewire lumenin the stent delivery balloon catheter during advancement within thevessel. This may happen when the blood vessel is tortuous, diffuselydiseased, severely calcified, or when there is reduced support from theguiding catheter. If a clinician attempts to advance the stent deliveryballoon catheter along an unstable distal free tip of the guidewire,there is a risk of vessel damage, including vessel dissection.Accordingly, a clinician often needs to remove the stent deliveryballoon catheter and reintroduce an angioplasty balloon catheter overthe guidewire to perform additional angioplasty procedures. This exposesan additional risk for the patient health, reduces efficiency of theprocedure, abandonment without placement of the therapeutic device andis extremely expensive.

Given a growing patient population with conditions associated with asubstantial vessel wall calcification, especially in patients sufferingdiabetes and/or chronic kidney disease, need for intravascular therapiesincreases dramatically. There is a patient population in which currenttherapies may be inefficient and/or ineffective. Thus, there is a needfor an improved intravascular technology that permits intravasculardeployment of a therapeutic element, such as a stent, in a controlledand robust manner.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a systemand a method for deployment of a therapeutic element (such as a stent)in a tube-like internal structure in a patient's body, for exampleintravascular, or other passages, such as the bile duct or uretericduct, in a controlled and robust manner that would support a reducednumber of equipment exchanges needed to deploy the therapeutic device inproximity to a lesion site within a blood vessel, while efficientlysecuring (anchoring) a delivery component, such as a guidewire, withinthe blood vessel during advancement of the therapeutic element to thelesion site.

It is another object of the present invention to provide a lockingmechanism for releasably securing the balloon catheter in vivo to adelivery component, e.g., a guidewire, so that the balloon catheter,being secured to the guidewire, facilitates the delivery of additionalcomponents, e.g., a therapeutic delivery catheter, along the guidewireto a target site while enhancing the stability of the guidewire in theblood vessel, especially near the target site.

It is an additional object of the present invention to provide anintravascular delivery system which prevents the guidewire's distal endfrom uncontrollable motion throughout the vessel lumen, providing asufficient rigidity and stability of the guidewire in proximity to thetarget (lesion) site within a blood vessel, which is beneficial fordelivery of a therapeutic element, e.g., a stent to the target site.

It is a further object of the present invention to provide anintravascular delivery system using a lockable balloon catheter equippedwith a locking mechanism operating to anchor and stabilize the guidewirenear the target site within the blood vessel for superior delivery ofadditional intravascular components along the guidewire, resulting in areduced displacement of the distal end of the guidewire within the bloodvessel, thus attaining enhanced guidewire stability in vivo.

It is also an object of the present invention to provide a method ofusing the subject balloon catheter controllably lockable to a guidewirewithin the blood vessel of interest for delivering the balloon catheterto a lesion in the blood vessel over a guidewire, inflating the balloonwith a conventional balloon inflation system to pre-dilate the vesseland disrupt the lesion (such as, for example, calcified plaque, disposedon the luminal lining), subsequently deflating the balloon fordisplacement adjacent to the lesion, and locking the balloon to theguidewire by re-inflating the balloon. One or more additionalintravascular components may be subsequently delivered to the lesionsite while the subject balloon catheter remains locked to the guidewirewhich, in its turn, is anchored and stabilized within the vessel duringthe procedure.

In addition, it is an object of the present invention to provide a kinkresistant intravascular delivery system where the shaft of the catheteris enhanced with an additional support and/or a rail mechanism foradvancement of intravascular components along the guidewire while theballoon is in the locked or unlocked configuration.

In accordance with one aspect of the subject system, an intravascularsystem is provided for securely advancing a stent over a guidewire to alesion within a blood vessel (or the bile duct or the ureteric duct) ofa patient. The subject system may include an elongated catheter shafthaving a proximal region, a distal region, an inflation lumen extendinginternal of the elongated catheter shaft between the proximal region andthe distal region, and a guidewire lumen which extends between arapid-exchange (RX) port formed within the elongated catheter shaft anda distal tip of the balloon catheter.

A balloon is affixed at the distal region of the elongated cathetershaft. A proximal end of the balloon is positioned a short distance ofabout 5 mm-30 mm apart from the rapid-exchange (RX) port. Thisarrangement attains stability in advancement of the stent along theguidewire to the lesion site within the blood vessel proximal to therapid-exchange port while the balloon remains inflated within the bloodvessel.

A locking portion of the elongated catheter shaft is disposed inside theballoon and extends between the proximal and distal ends of the balloon.The locking portion of the elongated catheter shaft may be configured totransition within the balloon from an unlocked mode of operation (when adiameter of the guidewire lumen is sized to permit its slidabledisplacement relative to the guidewire disposed within the guidewirelumen) to a locked mode of operation. In the locked mode of operation,the locking portion of the elongated catheter shaft is compressed withinthe balloon to reduce the diameter of the guidewire lumen, so that thewalls of the guidewire lumen come into contiguous contact with theguidewire and become circumferentially coupled to and compress theguidewire to “anchor” the guidewire within the guidewire lumen.

The locking portion of the elongated catheter shaft may include aflexible material to facilitate the compression of the guidewire withthe walls of the guidewire walls. The flexible material may include abraided material. The braided material may be a metal composition andthe braided material may be coated with a polymer such that the lockingportion of the elongated catheter shaft within the balloon is fluidimpermeable.

The balloon catheter may have a plurality of radiopaque markers disposedalong the elongated catheter shaft. The radiopaque markers may bepositioned adjacent to the rapid-exchange port.

In accordance with another aspect of the subject system, a method isprovided for safe advancement of an intravascular delivery system over aguidewire along the balloon shaft to a lesion within a blood vessel of apatient. The method may include the steps of:

-   -   fabricating a balloon catheter lockable to a guidewire within        the blood vessel. The lockable balloon catheter includes an        elongated catheter shaft having a proximal region, a distal        region, a first lumen extending between the proximal region to        the distal region, and a second lumen extending distally from a        rapid-exchange (RX) port within the elongated catheter shaft.

A balloon is affixed to the elongated catheter shaft at the distalregion such that a proximal end of the balloon is displaced from therapid-exchange port a short distance of about 5 mm-30 mm to attain astable advancement of the therapeutic element (stent) over the deliverycomponent (guidewire) to the target site within the body lumen proximalto the rapid-exchange port while the balloon remains inflated within thebody lumen.

The elongated catheter shaft may be configured to transition within theballoon from an unlocked mode of operation (when a diameter of thesecond lumen is sized to permit the slidable movement of the deliverycomponent (guidewire) therein), to a locked state (when the elongatedcatheter shaft is compressed within the balloon to reduce the diameterof the second lumen to circumferentially contact the delivery component(guidewire) to lock the delivery component (guidewire) within the secondlumen, responsive to pressurization within the balloon).

The subject method further includes the steps of:

-   -   delivering the lockable balloon catheter to the lesion in the        blood vessel over the guidewire;    -   inflating a balloon of the lockable balloon catheter to dilate        the blood vessel and disrupt the lesion;    -   deflating the balloon;    -   displacing the deflated balloon on the balloon catheter past the        lesion within the blood vessel; and    -   locking the balloon catheter to the guidewire by re-inflating        the balloon.

Inflating the balloon compresses the walls of the second lumen withinthe balloon around the guidewire to lock the guidewire in place, andthus locks the balloon catheter to the guidewire.

The subject method continues by delivering another catheter (forexample, a stent catheter) over the guidewire to the lesion site whilethe lockable balloon catheter remains locked to the guidewire to anchorand stabilize the guidewire within the blood vessel.

The subject system and method reduces the number of equipment exchangesneeded to deploy the therapeutic devices at a lesion site within theblood vessel, while securing the delivery component within the bloodvessel during advancement of the therapeutic catheter to the lesionsite.

These and other objects and advantages of the subject system and methodwill become more apparent to a person of ordinary skill in the art uponreading the Detailed Description of the Subject Invention in conjunctionwith the Patent Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary embodiment of the subject lockable ballooncatheter;

FIG. 2 depicts an exemplary embodiment of the subject systemintravascular delivery which includes a therapeutic delivery catheter,sheaths, and a guidewire, for use with the balloon catheter shown inFIG. 1;

FIGS. 3A, 3B and 3C are schematic representations of the distal regionof the subject lockable balloon catheter shown in FIG. 1 depicted,respectively, in the unlocked state (FIG. 3A) and the locked state (FIG.3B), while FIG. 3C depicts a longitudinal cross-section of the subjectlockable balloon catheter in the locked mode of operation;

FIGS. 4A and 4B are schematic representations of the distal region of analternative embodiment of the subject balloon catheter formed with aflexible material at the locking portion of the subject catheter withinthe balloon to facilitate the operation of the subject lockable ballooncatheter in the unlocked mode of operation (FIG. 4A) and the locked modeof operation (FIG. 4B), respectively;

FIGS. 4C-4D show schematically a wire-like kink resistant mechanism(FIG. 4C) or an alternative kink resistant mechanism attached at the RXport (FIG. 4D) embedded at the distal region of the elongated shaftbetween the RX port and the balloon; and

FIGS. 5A-5L illustrate the exemplary steps of the intravascular deliveryprocedure using the subject lockable balloon catheter to deliver atherapeutic device to a target site within a blood vessel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-4D and 5A-5L depict a system for deployment of a therapeuticdevice within a tube-like internal structure of a patient's body (suchas a blood vessel (body lumen), or the bile duct, as well as uretericduct, etc.). Although the principles of the subject system and methodare applicable for treatment procedures associated with differentinternal passages (tube-like structures) within a patient's body, thefollowing description of the subject system design and operation will befocused on the intravascular applications.

The subject system includes a balloon catheter which is capable oflocking in position in vivo to a delivery component, such as, forexample, a guidewire, disposed within a blood vessel. Subsequent tolocking the lockable balloon catheter to the guidewire, another catheterfor delivery of a therapeutic device, such as a stent, may be advancedover the guidewire to a target site in the blood vessel while thelocking balloon catheter stably anchors the guidewire in place adjacentto the target site in the blood vessel.

The subject system is particularly well-suited for treating conditionsassociated with vessel wall tortuosity, diffuse disease, calcificationor poor guiding catheter support during ischemic cardiovascularsyndromes including the coronary vascular syndrome, sometimes referredto as coronary artery disease (CAD), as well as the peripheral vascularsyndrome, sometimes referred to as the peripheral artery disease (PAD).

Referring to FIG. 1, the subject intravascular delivery system 1includes a balloon catheter 10 which includes an elongated shaft 12extending between a proximal region 14 and a distal region 16 of theballoon catheter 10. A balloon 18 is mounted to the elongated shaft 12at the distal region 16. The elongated shaft 12 has a portion 17extended inside the balloon 18 (further referred to herein as a lockingportion 17).

The proximal region 14 of the elongated shaft 12 preferably includes ahandle 20 for helping a clinician to manipulate the lockable ballooncatheter 10.

A balloon inflation port 22 at the proximal end 23 of the proximalregion 14 is coupled to the interior 19 of the balloon 18 through aninflation lumen 24 extending within the elongated shaft 12, as depictedin FIGS. 3A-3C.

The handle 20 and the balloon inflation port 22 may be elements used inconventional balloon catheters, and are not detailed herein with furtherspecifics. Similar to the proximal region 14 of the subject lockableballoon catheter 10, the handle 20 and the balloon inflation port 22 maybe formed from materials conventionally used in the intravascularcatheters, e.g., polyethylene and/or polyterephthalate.

The lockable balloon catheter 10 preferably has a length and diametersuitable for use in a cardiac or peripheral vessel under treatment. Theballoon catheter 10 may have the length ranging from 60 cm to 180 cm anda diameter ranging from 1.0 mm to 60 mm.

The balloon 18 may assume a closed (deflated) configuration (shown inFIGS. 3A and 4A, 4C, 5B, 5D-5E, and 5H-5I), or an inflated (expanded)configuration (shown in FIGS. 1-2, 3B-3C, 4B, 4D, 5C, and 5F-5G). Shownin FIG. 1, the balloon 18 is depicted in an expanded configurationsuitable for dilating the blood vessel. The balloon 18 may be formed ofa noncompliant material (such as polyethylene), a semi-compliantmaterial (such as polyterephthalate), or a compliant material (such asnylon).

The balloon 18 may be sized and shaped for insertion in the blood vesselas appropriate for an intended therapy and a bodily lumen (blood vessel)under treatment. For example, the length of the balloon 18 may rangefrom 1 cm to 20 cm. The balloon 18 may have a diameter, in the expandedconfiguration, of about 1.0 mm-6.0 mm for insertion in smaller lumens(such as coronary vessels). Alternatively, the balloon 18 may have adiameter of about 4 mm-10 mm for insertion in larger lumens (such asperipheral vessels). The balloon 18 may also have a diameter of about 1cm-6 cm if the catheter 10 is used for the therapy associated with thethoracic or abdominal aorta.

The balloon 18 is preferably affixed to the locking portion 17 of theelongated shaft 12 via thermal bonds, glue welds, or other suitablemethods.

The balloon 18 is configured to expand when it is pressurized responsiveto the introduction of a fluid (air) through the balloon inflation port22 under control of a balloon inflation system 25.

The balloon inflation system 25 is operatively coupled to the ballooninflation port 22 in a fluidly sealed fashion to support passage of theinflation fluid 27 (such as, for example, saline, iodinated contrastmedia, or air) to and from the balloon 18.

The balloon inflation system 25, which is schematically depicted in FIG.1, may be a manual or an automatic system. In the preferred automaticembodiment, the balloon inflation system 25 may include an electronicsub-system, a pneumatic sub-system, and a control software with acorresponding user interface. The electronic sub-system, under controlof the control software, supplies power to solenoid pressure valves(which are fluidly coupled to the balloon inflation port 22) to controlthe pressurizing/depressurizing cycles of the operation of the subjectballoon system with the air flow.

The inflation lumen 24 is configured with and terminates, at its distalend, in a balloon inflation port 26, which is disposed within theinterior 19 of the balloon 18, preferably, in proximity to the balloon'sproximal end 33. The inflation lumen 24 extends internally of theelongated shaft 12 between the balloon inflation port 22 and the balloon18 to provide bi-directional passage of the fluid (air) therealong forpressurizing/de-pressurizing of the balloon 18.

In the pressurized state, the balloon 18 assumes the expanded (inflated)configuration (shown in FIGS. 1, 2, 3B-3C, 4B, 4D, 5C, and 5F-5G). Whilein the depressurized state, the balloon 18 assumes a deflated (closed)configuration (shown in FIGS. 3A, 4A, 4C, 5B, 5D, 5E, 5H, 5I, and 5J).

The subject intravascular delivery system 1 operates in conjunction witha delivery component 31, such as, for example, a guidewire. Theguidewire 31 is advanced inside the blood vessel towards (and preferablybeyond) the lesion site prior to the cardiac (or other intravascular)procedure. The intravascular delivery system 1 is subsequently displacedalong the guidewire 31 internally of the blood vessel to a positioncorresponding to a lesion site for pre-dilatation, or other treatment.

The lockable balloon catheter 10 is configured with a guidewire lumen 28extending internally the elongated shaft 12 between the rapid-exchange(RX) port 30 and the tapered tip 32. The guidewire 31 extends inside theguidewire lumen 28 and extends distally beyond the tapered tip 32.

The guidewire lumen 28 is sized to permit the passage of the guidewire31 therethrough. For example, the guidewire lumen 28 may be sized topermit the guidewire to be inserted therethrough to facilitatedisplacement of the distal region 16 to a desired location along theguidewire 31 in a patient's vasculature or an organ.

As shown in FIG. 3C, the guidewire lumen 28 may be located centrally inthe elongated shaft 12, or alternatively, may be off-center. Preferably,the guidewire lumen 28 is compressible responsive to actuation of theballoon inflation system 25 by a clinician, e.g., inflation of balloon18, to lock the guidewire 31 therein, as will be detailed in furtherparagraphs.

The elongated shaft 12 may preferably be formed of a flexible materialto facilitate compression of the guidewire lumen 28. The elongated shaft12 may be formed of a flexible material along its entire length, oralong a select portion(s) of its length, such as the locking portion 17within the balloon 18.

In the subject system 1, the lockable balloon catheter 10 is equippedwith a locking mechanism which includes and is supported by cooperationof the balloon inflation system 25, inflation lumen 24, balloon 18, andlocking portion 17 of the elongated shaft 12 to transform the subjectsystem between the locked mode of operation and the unlocked mode ofoperation.

In the locked mode of operation, the inflation of the balloon 18 is usedto lock the balloon catheter 10 to the guidewire 31. As an example, theinflation of the balloon 18 at a predetermined pressure (e.g., a highpressure), causes the locking portion 17 of the elongated shaft 12 topress against the guidewire 31 (as depicted in FIGS. 3B-3C, 4B, and 4D),thereby causing the walls of the guidewire lumen 28 (extending from theRX port 30 into the balloon 18) to compress around the deliveryguidewire 31, thus locking the guidewire 31 within the elongated shaft12. In the compressed configuration, the contiguous coupling between thewalls of the guidewire lumen 28 and the guidewire 31 prevents relativedisplacement between the guidewire 31 and the elongated shaft 12. Thus,the contiguous coupling between the walls of the guidewire lumen 28 andthe guidewire 31 resulted from the controlled pressurizing of theballoon 18, as needed by the therapeutic procedure, locks the guidewire31 to the elongated shaft 12 of the balloon catheter 10.

When the inflation system 25 of the locking mechanism deflates theballoon, the walls of the guidewire lumen 28 return to their originalconfiguration, thus releasing the guidewire from the coupling with theelongated shaft 12, thereby transitioning into the unlocked mode ofoperation. In the unlocked mode of operation, the guidewire and theelongated shaft 12 are free to be displaced one relative to the other.

The RX (Rapid Exchange) port 30 is formed at the elongated shaft 12 ashort distance from the proximal end 33 of the balloon 18. Thisarrangement permits the delivery of a therapeutic delivery catheteralong the guidewire 31 to a target site in a blood vessel while theballoon catheter 10 remains locked to the body lumen, as shown in FIGS.5G-5J, and as will be detailed in further paragraphs.

For example, while a typical rapid-exchange port is conventionallydisplaced at least 15 cm from a balloon, the RX port 30 in the subjectsystem 1 may be disposed much closer, e.g., about 1-5 mm to 30 mm fromthe subject balloon's proximal end 33.

The compactness of the subject structure has a beneficial result, sincethe guidewire 31 exits from the elongated shaft 12 via the RX port 30within the blood vessel, and the therapeutic delivery catheter can bepositioned in proximity to the RX port 30 and the balloon 18 while theballoon 10 remains securely locked to the guidewire 31 in the bodylumen, thus providing favorable stable conditions for stent delivery.The therapeutic delivery catheter is thus anchored and stabilized withinthe body lumen.

The subject balloon catheter 10 may include one or more radiopaquemarkers to facilitate positioning of the balloon catheter 10 underfluoroscopic imaging. As shown in FIG. 1, the balloon catheter 10includes radiopaque markers 34, 36, 38, 40, and 42 positioned along theelongated shaft 12. The radiopaque markers may be fabricated fromconventional materials, such as platinum or iridium. The radiopaquemarkers 34 and 36 are positioned adjacent to the distal end 37 and theproximal end 33 of the balloon 18, respectively, for visualizing thelocation of the balloon 18 in the blood vessel. The radiopaque marker 38is positioned adjacent to the RX port 30 to permit visualization of thelocation of the RX port 30. The radiopaque markers 40 and 42 are shaftmarkers and may be displaced about 90 and 100 cm, respectively, from thedistal end (tip) 32 of the elongated shaft 12.

FIG. 2 shows an alternative configuration of the subject intravasculardelivery system which uses the lockable balloon catheter 10 shown inFIG. 1. The system includes a therapeutic delivery catheter, one or moresheaths, and the delivery component. In the illustrated example, shownin FIG. 2, the system 50 includes the lockable balloon catheter 10, asheath 52, a sheath 54, a delivery component (guidewire) 56, and atherapeutic delivery catheter 60.

The sheath 52 is sized and shaped for intravascular delivery procedure.The sheath 52 constitutes a lumen to permit the lockable ballooncatheter 10 to be disposed therein for a delivery procedure.

The sheath 54 is sized and shaped for intravascular delivery andconstitutes a lumen to permit the therapeutic delivery catheter 60 to bedisposed therein for the intravascular delivery. The sheaths 52 and 54may be conventional sheaths used in intravascular procedures.

The delivery component 56 is sized and shaped for the intravasculardelivery procedure, and may be a guidewire, as illustrated. In oneexample, the delivery component 56 is a conventional guidewire used inintravascular procedures.

The therapeutic delivery catheter 60 is designed to intravascularlydeliver a therapeutic device (such as a stent) to a target site in abody lumen. The therapeutic delivery catheter 60 includes an elongatedshaft 62 having a proximal region 64 and a distal region 66. A balloon68 is mounted at the distal region 66 of the elongated shaft 62.

The proximal region 64 of the elongated shaft 62 is manipulated by aclinician. For this purpose, the proximal region 64 is equipped with ahandle 67. A balloon inflation port 72 is coupled to the interior 73 ofthe balloon 68 through an inflation lumen 75 extending internally alongthe elongated shaft 62.

A guidewire port 74 is coupled to the distal region 66 of the elongatedshaft 62 through a guidewire lumen 77. The guidewire lumen 77 is sizedto receive the guidewire 56 therein.

The handle 67 and the ports 72 and 74 are conventional elements, andsimilar to the proximal region 64 of the therapeutic delivery catheter60, may be formed from materials conventionally used for fabrication ofintravascular catheters, e.g., polyethylene or polyterephthalate. Thetherapeutic delivery catheter 60 preferably has a length and diametersuitable for use in the therapeutic procedures associated with cardiacor peripheral vessels.

The therapeutic delivery catheter 60 is configured to deliver atherapeutic device 70, which may be, for example, a stent. In theexample, depicted in FIG. 2, the therapeutic delivery catheter 60includes the balloon 68 disposed at a predetermined location at thedistal region 66 of the elongated shaft 62 within the therapeutic device70. When the balloon 68 is expanded (as the result of introducing thefluid (or air) into the balloon inflation port 72), it causes thetherapeutic device 70 to expand from a delivery (deflated) configurationto a deployed (expanded) configuration.

While the therapeutic delivery catheter 60 is depicted in the exemplaryembodiment as a balloon catheter for stent delivery (e.g., bare metalstent or drug-eluting stent), the therapeutic delivery catheter 60 mayalso deliver other types of therapeutics and may be, for example, adrug-delivery catheter, a balloon catheter, a drug-eluting ballooncatheter, or an energy delivery catheter. Examples of drugs that may bedelivered include anti-mitotic drugs, regenerative agents,anti-inflammatory agents, anti-allergenic agents, anti-bacterial agents,anti-viral agents, anticholinergic agents, antihistamines,antithrombotic agents, anti-scarring agents, antiproliferative agents,antihypertensive agents, anti-restenosis agents, healing promotingagents, vitamins, proteins, genes, growth factors, cells, stem cells,vectors, RNA, and/or DNA. The energy delivery catheter may includenumerous types of energy, including the ultraviolet light, ultrasound,resistive heat, radio frequency (RF), and cryogenic.

FIGS. 3A, 3B, and 3C depict the distal region 16 of one embodiment ofthe subject lockable balloon catheter 10. FIGS. 3A and 3B show,respectively, the balloon catheter 10 in the unlocked state (FIG. 3A)and the locked state (FIG. 3B), while FIG. 3C shows the longitudinalcross-section of the subject balloon catheter 10 in its locked state.

In FIG. 3A, the elongated catheter shaft 12 is in the unlocked state(mode of operation). In the unlocked state, the diameter of theguidewire lumen 28 is sized to support the slidable movement(displacement) of guidewire 31 therein.

The elongated shaft 12 is designed to transition to the locked state,shown in FIGS. 3B-3C, by compressing the locking portion 17 of theelongated shaft 12 inside the balloon 18 to reduce the diameter of theguidewire lumen 28 when the balloon 18 is inflated, so that the walls ofthe elongated shaft 12, at its locking portion 17, circumferentiallyembrace and press on the guidewire 31 to lock the guidewire 31 withinthe guidewire lumen 28. For example, introduction of the fluid (air)into the balloon 18 via the inflation lumen 24 and the balloon inflationport 26 inflates the balloon 18 and pressurizes the internal space 19 ofballoon 18 to a level that compresses the walls of the locking portion17 of the elongated catheter shaft 12, as shown in FIGS. 3B and 3C.

Advantageously, the inflation of the balloon 18, in addition to couplingthe guidewire lumen 28 to the guidewire 31, may also increase thecoupling of the walls of the balloon 18 with the inner lining of thebody lumen 100, thereby anchoring the balloon 18 within the body lumento stabilize the locked guidewire 31 within the body lumen 100, as shownin FIGS. 3A-3B.

FIGS. 4A and 4B depict the distal region of a catheter 10′ similar tothat shown in FIGS. 3A, 3B, and 3C. The catheter 10′ includes a flexiblematerial 44 at the locking portion 17′ of the elongated shaft 12′ withinthe balloon 18′ to facilitate the locking mechanism. The lockableballoon catheter 10′ is fabricated in the configuration similar to thelockable balloon catheter 10 shown in FIGS. 1-2 and 3A-3C, so thatsimilar components are indicated with similar number with prime. Theflexible material 44 may extend along the elongated shaft 12′ onlywithin balloon 18′ (only at the locking portion 17′) or may extendfurther along the entire length of the elongated shaft 12′. The flexiblematerial 44 may be formed from a braided material, e.g., braided metal,such as stainless steel. The braided material may be coated with anotherfluid impermeable material, such as a polymer. As is shown, the flexiblematerial 44 at the locking portion 17′ is configured to compress uponactuation, e.g., inflating and pressurizing of the balloon 18, therebylocking the guidewire lumen to the delivery component 56′.

Referring to FIGS. 4C-4D, in an alternative implementation, the subjectballoon catheter 10″ may be enhanced by a kink resistant mechanism 120.A portion of the subject system between the RX port 30 and the balloon18, is vulnerable to possible sharp twists, buckling, and/or curving ofthe elongated catheter shaft 12 when the inflated balloon 18 is pulledalong the guidewire as another delivery device (stent) is advanced overthe guidewire.

In order to prevent the unwanted deviation of the elongated cathetershaft 12 from the straight configuration during the cardiac procedure,the subject system 10″, in its alternative implementation, is configuredwith the kink resistant mechanism 120. The kink resistant mechanism 120may be formed with a Nitinol/Steel wire-like member (or stampedelongated member) 122 affixed internally along the elongated cathetershaft 12 between the RX port 30 and the balloon 18 (as shown in FIG.4C). Alternatively, the kink resistant mechanism 120 may be formed fromNitinol/Steel as an elongated member 124 configured with elongated parts126 connected (preferably integrally therewith) through a centralcircular (or oval) shaped part 128. The elongated member 124 may beembedded in the wall of the elongated catheter shaft 12, as well as maybe attached internally or externally along the elongated catheter shaft12 (as shown in FIG. 4D) with the central part 128 secured to the RXport 30 in alignment with the periphery of the RX port 30.

Alternatively, the kink resistant mechanism 120 may be represented byboth members 122 and 124 (combined embodiment) embedded in the wall ofthe elongated catheter shaft 12 or secured (internally or externally) tothe wall of the elongated catheter shaft 12 between the RX port 30 andthe balloon 18.

In either configurations, either embedded, or secured internally orexternally, or in the combined embodiment, the kink resistant mechanism120 prevents sharp twisting, buckling, and curling of the elongatedcatheter shaft 12, and thus provided a robust system capable ofwithstanding various scenarios of cardiac procedures.

Although shown in FIGS. 4C-4D in application to the embodiment depictedin FIGS. 4A-4B, the kink resistant mechanism 120 is applicable to allalternative embodiments of the subject system shown in FIGS. 1-5I.

The subject method may use the lockable balloon catheter 10 and 10′ toperform an interventional procedure. However, only as an example, thesubject method is described infra for use with the lockable ballooncatheter 10 depicted in FIGS. 1, 2, and 3A-3C. The alternative catheters10′ shown in FIGS. 4A-4B may also be used in a manner similar to thatdescribed below.

In FIG. 5A, delivery component (guidewire) is advanced inside the bloodvessel and is delivered to a target location. In this example, thedelivery component 56 (illustratively, a guidewire) is placed in thevessel V at the location of a lesion L as determined by the fluoroscopicimaging technique, contrast agents and/or conventional interventionaltechniques.

As shown in FIG. 5B, the balloon catheter 10 is backloaded onto thedelivery component 56 by inserting the proximal end 80 of the guidewire56 into the distal opening 82 of the guidewire lumen 28 located in thedistal tip 32 of the balloon catheter 10. The catheter 10 is advancedthrough the patient's vasculature V until the distal region 16 isdisposed at the target location (e.g., the lesion L), as determinedusing the radiopaque markers on the catheter shaft 12 and thefluoroscopic imaging. When so disposed in a patient's vessel V, thedistal region 16 of the balloon catheter 10 will appear as depicted inFIG. 5B. During the delivery procedure, the balloon 18 of the catheter10 may be wrapped or folded in the closed configuration.

Alternatively, a delivery sheath (such as sheath 52 shown in FIG. 2) maybe disposed over the distal region 16 of the balloon catheter 10 toattain a smooth outer surface for the lockable balloon catheter 10. Thesheath 52 then may be retracted proximally to expose the distal region16 once it has reached the desired location L in vessel V. As shown, theguidewire 56 is disposed in the guidewire lumen 28 within the balloon 18and exits the catheter 10 at the guidewire RX port 30.

Referring now to FIGS. 5C and 1, a conventional inflator system 25 iscoupled to the inflation port 22, and the inflation medium 27, such as,for example, saline or a saline diluted iodinated contrast agent, isdelivered via the inflation lumen 24 to the balloon 18 to cause theballoon's expansion. In the inflated configuration, the walls 84 of theballoon 18 contact the lesion L and the intima of the vessel V to dilatethe vessel V and disrupt the lesion L. Subsequently, as shown in FIG.5D, the balloon 18 is deflated.

Referring now to FIG. 5E, the balloon 18, in its deflated configuration,is advanced along the distal end 86 of the guidewire 56 to a locationadjacent to, but beyond, the target site L within the body lumen V. Forexample, the lockable balloon catheter 10 and the delivery component 56may be moved distally within the vessel V such that the RX port 30 isdisposed distal to the target site L, and the proximal end 80 of thedelivery component (guidewire) 56 is located outside of the catheter 10and extends through the target site within the body lumen V.

Subsequently, as shown in FIG. 5F, the balloon catheter 10 is locked tothe delivery component 56 by introduction of the fluid 27 into theballoon 18 via the inflation lumen 24 and the balloon inflation port 26.Introduction of the fluid 27 under high pressure inflates the balloon 18and pressurizes the internal space 19 of the balloon 18 to a level thatcompresses the elongated catheter shaft 12 and forces the guide lumen 28into tight contact with the delivery component 56 contained therein,thus compressing around the delivery component 56 and locking thedelivery component 56 to the elongated shaft 12. In addition, theinflation of the balloon 18 causes the walls 84 of the balloon 18 withor without a contiguous contact with the internal lining of the vesselV, thereby anchoring the balloon 18 within the vessel V to stabilize thelocked delivery component 56 within the vessel V.

As presented in FIG. 5G, when the balloon catheter 10 is locked to thedelivery component 56, and the balloon catheter 10 and the deliverycomponent 56 are anchored in place within the body lumen (with orwithout contact of the walls 84 of the balloon 18 with the internallining of the blood vessel V), the therapeutic delivery catheter 60 maybe delivered along the delivery component 56 to align the therapeuticdevice 70 with the target site L. During delivery, the balloon 68 oftherapeutic delivery catheter 60 may be folded. Alternatively, adelivery sheath (such as the sheath 54 shown in FIG. 2) may be disposedover the distal region 66 of the catheter 60 to form a smooth outersurface for the therapeutic delivery catheter 60. The sheath 54subsequently may be retracted proximally to expose the distal region 66once it reaches the desired location in the vessel V. In the body lumen,the lockable balloon catheter 10 remains separate from the therapeuticdelivery catheter 60, although both use the same delivery component 56in the lumen V.

Subsequently, as shown in FIG. 5H, the lockable balloon catheter 10 isunlocked from the delivery component 56. For example, deflation of theballoon 18 may result in decompression of the elongated shaft 12 so thatthe diameter of the guidewire lumen 28, at its locking part 17, expandsto permit slidable displacement of the guidewire 56 therewithin.

As shown in FIG. 5I, the delivery component (guidewire) 56 is thenremoved from the lockable balloon catheter 10. For example, the deliverycomponent 56 may be pulled proximally while the lockable ballooncatheter 10 is held in place until the distal end 86 of the deliverycomponent 56 exits the RX port 30. Alternatively, the lockable ballooncatheter 10 can be moved distally while the delivery component 56 isheld in place until the distal end 86 of the delivery component 56 exitsthe RX port 30.

As shown in FIG. 5J, the lockable balloon catheter 10 is then displacedproximally past the target site L while the therapeutic deliverycatheter 60 remains positioned at the target site L within the bloodvessel V. The lockable balloon catheter 10 may be removed entirely fromthe patient's blood vessel V, or may be displaced a suitable proximaldistance to permit the therapeutic deployment. Alternatively, theballoon catheter may be moved to a different vessel or a branch of thevessel V.

As shown in FIG. 5K, the therapeutic device (stent) 70 is then deployedat the target site L. For example, the balloon 68 may be inflated toexpand, thereby causing the therapeutic device 70 to expand and contactthe inner wall of the vessel V.

Subsequently, as shown in FIG. 5L, in the case when the therapeuticdevice (stent) 70 is designed for implantation, the therapeutic deliverycatheter 60 is removed, leaving the therapeutic device 70 implanted atthe target location L.

Although this invention has been described in connection with specificforms and embodiments thereof, it will be appreciated that variousmodifications other than those discussed above may be resorted towithout departing from the spirit or scope of the invention as definedin the appended claims. For example, functionally equivalent elementsmay be substituted for those specifically shown and described, certainfeatures may be used independently of other features, and in certaincases, particular locations of elements, steps, or processes may bereversed or interposed, all without departing from the spirit or scopeof the invention as defined in the appended claims.

What is claimed is:
 1. An intravascular delivery system for securelyadvancing a stent along a guidewire to a lesion site within a bloodvessel of a patient, the system comprising: at least a lockable ballooncatheter including: an elongated catheter shaft having a proximalregion, a distal region, and a rapid-exchange (RX) port formed in wallsof said elongated catheter shaft between said proximal and distalregions thereof, an inflation lumen extending within said elongatedcatheter shaft from said proximal region to said distal region, aguidewire lumen extending distally from said RX port within theelongated catheter shaft to and along said distal region; a balloonhaving a proximal end and a distal end and secured to said elongatedcatheter shaft at the distal region, said proximal end of said balloonbeing displaced from said RX port a predetermined distance; and alocking mechanism operatively coupled between said balloon and saidelongated catheter shaft, said locking mechanism being configured totransition said elongated catheter shaft between an unlockedconfiguration, when a diameter of said guidewire lumen permits slidablemovement of the guidewire therein, and a locked configuration, when,responsive to inflation of said balloon, walls of said elongatedcatheter shaft are compressed by a pressure inside said balloon toreduce the diameter of the guidewire lumen to circumferentially contactthe guidewire to prevent displacement of said guidewire within theguidewire lumen.
 2. The system of claim 1, wherein said inflation lumenis configured with and terminates in a balloon inflation port positionedwithin said balloon in proximity to said proximal end thereof, whereinsaid locking mechanism includes said balloon, said walls of saidelongated catheter shaft, said inflation lumen, and a balloon inflationsystem operatively coupled to said inflation lumen at said proximalregion of said elongated catheter shaft, said balloon inflation systembeing controlled to inflate and deflate said balloon via said inflationlumen and said balloon inflation port formed thereat, wherein saidballoon is inflated to transition said lockable balloon catheter in saidlocked configuration, and wherein said balloon is deflated to transitionsaid lockable balloon catheter in said unlocked configuration.
 3. Thesystem of claim 2, where said balloon assumes an expanded configurationin said locked configuration of said lockable balloon catheter, andwherein, in said expanded configuration, said locking mechanism isfurther augmented by a contact between walls of said balloon andinternal walls of a blood vessel between said proximal and distal endsof said balloon.
 4. The system of claim 1, where said elongated cathetershaft comprises a flexible material disposed between said proximal anddistal ends of said balloon to facilitate compression of at least aportion of the walls of said elongated catheter shaft.
 5. The system ofclaim 4, wherein the flexible material comprises a braided material,wherein the braided material includes a metal, the braided materialbeing coated with a polymer, wherein a portion of said elongatedcatheter shaft between said proximal and distal ends of said balloon isfluidly impermeable.
 6. The system of claim 1, further comprising a kinkresistant mechanism affixed to said elongated catheter shaft andextending therealong between said RX port and said proximal end of saidballoon, said kink resistant mechanism being formed as a reinforcingelongated structure embedded in, or secured internally or externally to,a wall of said elongated catheter shaft external to said guidewirelumen.
 7. The system of claim 1, further comprising a plurality ofradiopaque markers disposed along said elongated catheter shaft.
 8. Thesystem of claim 7, wherein a radiopaque marker of the plurality ofradiopaque markers is positioned adjacent to the RX port.
 9. The systemof claim 1, wherein the distance between the RX port and the proximalend of the balloon ranges from 1 mm to 30 mm.
 10. An intravasculardelivery system for securely advancing a therapeutic device along adelivery component to a target site within a body lumen of a patient,the system comprising: a lockable balloon catheter, including: anelongated catheter shaft having a proximal region, a distal region, anda rapid-exchange (RX) port formed in walls of said elongated cathetershaft between said proximal and distal regions thereof, an inflationlumen extending within said elongated catheter shaft from said proximalregion to said distal region, a delivery component lumen extendingdistally from said RX port within the elongated catheter shaft to andalong said distal region; a balloon having a proximal and a distal endand secured to said elongated catheter shaft at the distal region, saidproximal end of said balloon being displaced from said RX port apredetermined distance; and a locking mechanism operatively coupledbetween said balloon and said elongated catheter shaft, said lockingmechanism being configured to transition said elongated catheter shaftbetween an unlocked configuration, when a diameter of the deliverycomponent lumen permits slidable movement of the delivery componenttherein, and a locked configuration, when, responsive to inflation ofsaid balloon, walls of said elongated catheter shaft are compressed bypressure within the balloon to reduce the diameter of the deliverycomponent lumen to circumferentially contact the delivery component toprevent displacement of said delivery component within the deliverycomponent lumen, responsive to inflation of said balloon; and atherapeutic device delivery catheter carrying a therapeutic device at adistal portion thereof and operatively coupled to said deliverycomponent for displacement to a target site within a body lumen alongsaid delivery component; whereby said therapeutic element is advancedalong said delivery component to the target site within the body lumenin proximity to the RX port while said balloon is inflated and anchoredwithin the body lumen.
 11. The system of claim 10, wherein the deliverycomponent is a guidewire.
 12. The system of claim 10, wherein thetherapeutic element is a stent.
 13. The system of claim 10, wherein saidelongated catheter shaft is formed with a flexible material within saidballoon to facilitate compression of the walls of said elongatedcatheter shaft.
 14. The system of claim 13, wherein the flexiblematerial comprises a braided material.
 15. A method for intravasculardelivery of a therapeutic device by secure advancement along a guidewireto a lesion site within a blood vessel of a patient, the methodcomprising: configuring at least a lockable balloon catheter including:an elongated catheter shaft having a proximal region, a distal region,and a rapid-exchange (RX) port formed in walls of said elongatedcatheter shaft between said proximal and distal regions thereof, aninflation lumen extending within said elongated catheter shaft from saidproximal region to said distal region, a guidewire lumen extendingdistally from said RX port within the elongated catheter shaft to andalong said distal region; a balloon having a proximal and a distal endand secured to said elongated catheter shaft at the distal region, saidproximal end of said balloon being displaced from said RX port apredetermined distance; and a locking mechanism operatively coupledbetween said balloon and said elongated catheter shaft, said lockingmechanism being configured to transition said elongated catheter shaftbetween an unlocked configuration, when a diameter of the guidewirelumen permits slidable movement of the guidewire therein, and a lockedconfiguration, when, responsive to inflation of said balloon, walls ofsaid elongated catheter shaft are compressed to reduce the diameter ofthe guidewire lumen to circumferentially contact the guidewire toprevent displacement of said guidewire within the guidewire lumen;delivering said lockable balloon catheter to the lesion site in theblood vessel over a guidewire; inflating said balloon of said lockableballoon catheter to dilate the blood vessel and disrupt the lesion;deflating said balloon, and moving said balloon adjacent to the lesionsite within the blood vessel; re-inflating said balloon, thus lockingsaid balloon catheter to the guidewire; and delivering a second catheterover said guidewire to the lesion site.
 16. The method of claim 15,wherein the second catheter comprises a stent, the method furthercomprising the step of: delivering the stent at the lesion site withinthe blood vessel.
 17. The method of claim 16, further comprising thestep of: prior to delivering the stent, removing said lockable ballooncatheter from the blood vessel.
 18. The method of claim 15, wherein thesecond catheter is delivered while the balloon catheter remains lockedto the guidewire to anchor and stabilize the guidewire within the bloodvessel within said lockable balloon catheter.
 19. The method of claim15, wherein locking of said lockable balloon catheter to said guidewirecomprises the step of inflating said balloon.
 20. The method of claim19, wherein inflation of said balloon causes compression of said wallsof said guidewire lumen within said balloon around the guidewire.
 21. Adelivery system for securely advancing a stent along a guidewire to alesion site within an internal passage in a patient's body, the internalpassage including at least one of a blood vessel, a bile duct, and anureteric duct, the system comprising: at least a lockable ballooncatheter including: an elongated catheter shaft having a proximalregion, a distal region, and a rapid-exchange (RX) port formed in wallsof said elongated catheter shaft between said proximal and distalregions thereof, an inflation lumen extending within said elongatedcatheter shaft from said proximal region to said distal region, aguidewire lumen extending distally from said RX port within theelongated catheter shaft to and along said distal region; a balloonhaving a proximal end and a distal end and secured to said elongatedcatheter shaft at the distal region, said proximal end of said balloonbeing displaced from said RX port a predetermined distance; and alocking mechanism operatively coupled between said balloon and saidelongated catheter shaft, said locking mechanism being configured totransition said elongated catheter shaft between an unlockedconfiguration, when a diameter of said guidewire lumen permits slidingmovement of the guidewire therein, and a locked configuration, when,responsive to inflation of said balloon, walls of said elongatedcatheter shaft are compressed by a pressure inside said balloon toreduce the diameter of the guidewire lumen to circumferentially contactthe guidewire to prevent displacement of said guidewire within theguidewire lumen.